King County · System ID 41997 · Community water system
Is Lakehaven Water And Sewer District’s water safe? PFAS test results (King County, WA)
PFAS detected — below state action levels
Lakehaven Water And Sewer District detected PFAS in 9 of its 23 tested water sources; every result in the current state dataset (2021–present) is below Washington’s state action levels (latest test May 2026).
Community water system serving King County · 46,077 connections · about 148,809 people.
At least one individual sample measured at or above a federal MCL value (4 ng/L for PFOA/PFOS; 10 ng/L for PFHxS, PFNA, HFPO-DA). Compliance with the federal standard is judged on running annual averages at the tap — a single source sample at that level is a flag, not a violation.
PFAS results on record for Lakehaven Water And Sewer District
| Analyte | Highest result | WA action level | Federal MCL | Detected at source |
|---|---|---|---|---|
| PFPeA Perfluoropentanoic acid | 11 ng/L | — | — | WELL 18 |
| PFHxA Perfluorohexanoic acid | 8 ng/L | — | — | WELL 18 |
| PFOS Perfluorooctanesulfonic acid | 8 ng/L | 15 ng/L | 4 ng/L | WELL 15, WELL 18, Well 15A, Well 19A |
| PFHxS Perfluorohexanesulfonic acid | 7 ng/L | 65 ng/L | 10 ng/L | Well 16, Well 17A, Well 19A |
| PFBS Perfluorobutanesulfonic acid | 5 ng/L | 345 ng/L | — | WELL 15, WELL 18, Well 10, Well 15A, Well 16, Well 17A, Well 19A, Well 20A, Well 25 |
| PFOA Perfluorooctanoic acid | 5 ng/L | 10 ng/L | 4 ng/L | WELL 15, WELL 18, Well 19A |
| PFBA Perfluorobutanoic acid | 4 ng/L | — | — | WELL 18, Well 19A |
| PFHpA Perfluoroheptanoic acid | 3 ng/L | — | — | WELL 18 |
What this means
PFAS was detected in 9 of the 23 sources tested for this system, and every result in the current state dataset (2021–present) is below Washington’s state action levels — the thresholds at which the state requires customer notification and action. Detected-but-below-action-level is exactly what it sounds like: PFAS is present in at least one source at low levels, and the state does not currently require the utility to act on it.
If you’d rather not drink detectable PFAS at any level, the at-the-tap option we plan to offer is under-sink reverse osmosis — manufacturer test data shows RO membranes reduce PFAS. See the planned systems.
These results describe the water system’s sources (wells, intakes), not any individual tap — utilities blend, treat, and rotate sources. Data: Washington State Department of Health public PFAS results and Drinking Water Service Areas, dataset updated 2026-07-22. Latest test on record for this system: 2026-05-13. Informational only — not a certification of water quality and not health advice. If you have concerns about your drinking water, contact your utility or the WA DOH Office of Drinking Water.
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